Mustard Oil Glucosides: Feeding Stimulants for Adult Cabbage Flea Beetles, Phyllotreta cruciferae (Coleoptera: Chrysomelidae)1

Mustard oil glucosides, principal constituents of the host plants of adult flea beetles, Phyllotreta cruciferae Goeze, stimulated a feeding response on bean leaves, normally unacceptable hosts. Distinct glucoside preferences were found when bean leaves were cultured in 5 different glucosides (0.5% aqueous solutions) and offered in laboratory feeding experiments. When bean leaves were cultured in different sinigrin concentrations, the minimum concentration required to stimulate feeding was 0.01% (153 ppm) sinigrin. The amount of feeding increased with sinigrin concentration up to 3.0% (45,900 ppm) sinigrin but dropped off drastically at 4.0% (61,200 ppm) sinigrin. These findings suggest that mustard oil glucosides play a significant role in host-plant selection by P. cruciferae adults.